[time-nuts] RFTG-m-RB

[Bruce Griffiths]

John Ackermann N8UR wrote:
> IIRC, the 3586 wants a sine wave reference, and gets fairly unhappy if
> it doesn't see one.
>
> Of course, another option is to stick a low pass filter following the 10
> MHz square wave; knock off the odd harmonics, and you'll have a sine
> wave again.
>
> John
>
>
>   
John


The phase shift tempco of a 10MHz bandpass filter can be fairly high and
a higher phase shift stability can be achieved by not using a 10MHz
bandpass filter.

1) Use a low pass filter with a small phase shift at 10MHz to eliminate
the higher frequency harmonics.
2) Use high Q bandstop filters with low phase shift at 10MHz to
eliminate the residual 30MHz (and other harmonics with significant
amplitude) harmonic
 Shunting the unwanted harmonics to ground with a high Q series tuned
circuits may be the best approach when the filter system is driven from
a high impedance (eg a collector or drain).

The resulting filter system is more complex but has a lower phase shift
tempco.

Bruce

Bruce